Pixel circuit, display panel, and display device

ABSTRACT

A pixel driving circuit includes a signal loading component, a storage capacitor, a compensation component, a mirror component, and a drive transistor. In a data transmission stage, the signal loading component transmits a received image data signal to the gate of a drive transistor, which is stored in a storage capacitor; and in a threshold voltage compensation stage, the compensation component connects the gate of the drive transistor to the source of the drive transistor so as to generate a drive signal dependent upon the threshold voltage of the drive transistor from the signal stored in the storage capacitor and to drive an organic light emitting diode to emit light, thus eliminating an influence of the threshold voltage of the drive transistor on the current through the organic light emitting diode and preventing the brightness of the organic light emitting diode from varying over its operating period of time.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part (CIP) application of U.S.patent application Ser. No. 14/557,257, filed on Dec. 1, 2014, whichclaims priority to Chinese patent application No. 201410442485.X,entitled “PIXEL CIRCUIT, DISPLAY PANEL, AND DISPLAY DEVICE”, filed withthe State Intellectual Property Office of People's Republic of China onSep. 2, 2014, the entire contents of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to the field of display technologies, andmore particularly to a pixel circuit, a display panel and a displaydevice.

BACKGROUND OF THE INVENTION

Active Matrix Organic Light Emitting Diode (AMOLED) displays have beenwidely used due to their wide viewing angle, good color contrast effect,high response speed, low cost and other advantages. However, a drift inthreshold voltage may result from the problem of non-uniformity of aThin Film Transistor (TFT) array substrate in a process flow.

As illustrated in FIG. 1, a traditional 2T1C pixel circuit includes aswitch transistor T1, a drive transistor T2, a storage capacitor C1 andan Organic Light Emitting Diode (OLED). A scan signal, denoted Scan, isreceived at the gate of the switch transistor T1, and the scan signalScan includes a signal on a gate line connected with the pixel circuit.An image data signal, denoted Data, is received at the source (or thedrain) of the switch transistor T1, the drain (or the source) of theswitch transistor T1 is connected with a first end of the storagecapacitor C1, a first drive signal VDD is received at a second end ofthe storage capacitor C1, the first drive signal VDD is received at thesource of the drive transistor T2, the gate of the drive transistor T2is connected with the first end of the storage capacitor C1, the drainof the drive transistor T2 is connected with a first end of the OLED,and a second drive signal VSS is received at a second end of the drivetransistor T2. When a start signal in the scan signal Scan is receivedat the gate of the switch transistor T1, the switch transistor T1 isturned on, and the image data signal Data received at the source (or thedrain) of the switch transistor T1 is transferred to the drain (or thesource) of the switch transistor T1 and stored in the storage capacitorC1, wherein the drive transistor T2 is controlled by the image datasignal Data together with the first drive signal VDD to operate so thatthe OLED is driven by the current at the drain of the drive transistorT2 to emit light. In such a 2T1C pixel circuit, the current at the drainto drive the OLED to emit light is dependent upon the threshold voltageof the drive transistor T2, and with a long operating time a drift inthreshold voltage of the drive transistor T2 may result from thecharacteristic of the transistor per se, thereby varying a currentflowing through the organic light emitting diodes in an array of pixelcircuits, and imposing a direct influence upon the brightness of thelight emitting diodes, which will be more apparent in a high-power lightemitting diode display element.

In summary, a drift in threshold voltage of a drive transistor in apixel element over its operating period of time may have the same OLEDdriven by varying current to emit light upon reception of the same imagedata signal during different periods of time so that the brightness ofthe OLED will vary over its operating period of time.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention provide a pixel circuit, a displaypanel and a display device.

An embodiment of the present invention provides a pixel circuit fordriving an organic light emitting diode. The pixel circuit includes asignal loading component, a storage capacitor, a compensation component,a mirror component and a drive transistor, wherein the signal loadingcomponent is configured to transmit a received image data signal to thegate of the drive transistor in a data transmission stage; the storagecapacitor is configured to store the signal at the gate of the drivetransistor; the drive transistor is configured to generate the currentat the drain of the drive transistor according to the difference betweenthe signal at the gate of the drive transistor and a signal on thesource of the drive transistor in a light emission stage; thecompensation component is configured to connect the gate of the drivetransistor to the source of the drive transistor in a threshold voltagecompensation stage so as to generate a drive signal from the image datasignal stored in the storage capacitor in the data transmission stage;and the mirror component is configured to mirror the current, generatedby the drive transistor, at the drain thereof onto the organic lightemitting diode in the light emission stage, so that the organic lightemitting diode emits light with the difference in voltage between afirst power supply signal and a second power supply signal.

Another embodiment of the present invention provides a display panelincluding a pixel circuit according to the embodiment of the presentinvention.

Another embodiment of the present invention provides a display deviceincluding the display panel according to the embodiment of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a pixel circuit in the priorart;

FIG. 2 is a simplified block diagram of a pixel circuit according to afirst embodiment of the present invention;

FIG. 3 is a simplified block diagram of a pixel circuit according to asecond embodiment of the present invention;

FIG. 4 is a simplified circuit diagram of a pixel circuit according to athird embodiment of the present invention;

FIG. 5 is a simplified circuit diagram of a pixel circuit according to afourth embodiment of the present invention;

FIG. 6 is a simplified circuit diagram of a pixel circuit according to afifth embodiment of the present invention;

FIG. 7 is a simplified circuit diagram of a pixel circuit according to asixth embodiment of the present invention;

FIG. 8 is an operational timing diagram of the pixel circuitsillustrated in FIG. 4 to FIG. 7;

FIG. 9 is an operational timing diagram of the pixel circuitsillustrated in FIG. 4 to FIG. 7;

FIG. 10 is a simplified circuit diagram of a pixel circuit according toa seventh embodiment of the present invention;

FIG. 11 is a simplified circuit diagram of a pixel circuit according toan eighth embodiment of the present invention;

FIG. 12 is a simplified circuit diagram of a pixel circuit according toa ninth embodiment of the present invention;

FIG. 13 is a simplified circuit diagram of a pixel circuit according toa tenth embodiment of the present invention;

FIG. 14 is an operational timing diagram of the pixel circuitsillustrated in FIG. 10 to FIG. 13;

FIG. 15 is an operational timing diagram of the pixel circuitsillustrated in FIG. 10 to FIG. 13;

FIG. 16 is a simplified block diagram of a display panel according to anembodiment of the present invention; and

FIG. 17 is a simplified block diagram of a display device according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention provide a pixel circuit, a displaypanel and a display device, wherein in a data transmission stage, asignal loading component transmits a received image data signal to thegate of a drive transistor, and the signal is stored in a storagecapacitor, and in a threshold voltage compensation stage, a compensationcomponent connects the gate of the drive transistor to the source of thedrive transistor to fetch the threshold voltage of the drive transistorso as to generate a drive signal dependent upon the threshold voltage ofthe drive transistor from the image data signal stored in the storagecapacitor in the data transmission stage and to further drive an organiclight emitting diode by the drive signal to emit light, thus eliminatingan influence of the threshold voltage of the drive transistor on drivecurrent flowing through the organic light emitting diode and preventingthe brightness of the organic light emitting diode from varying over itsoperating period of time.

Particular implementations of a pixel circuit, a display panel and adisplay device according to embodiments of the present invention will bedescribed below with reference to the drawings.

An embodiment of the present invention provides a pixel circuit fordriving an organic light emitting diode, the pixel circuit includes asignal loading component, a storage capacitor, a compensation component,a mirror component and a drive transistor.

The signal loading component is configured to transmit a received imagedata signal to the gate of the drive transistor in a data transmissionstage.

The storage capacitor is configured to store the signal at the gate ofthe drive transistor.

The drive transistor is configured to generate the current at the drainthereof according to the difference between the signal at the gate ofthe drive transistor and a signal on the source of the drive transistorin a light emission stage.

The compensation component is configured to connect the gate of thedrive transistor to the source of the drive transistor in a thresholdvoltage compensation stage so as to generate a drive signal from theimage data signal stored in the storage capacitor in the datatransmission stage.

The mirror component is configured to mirror the current, generated bythe drive transistor, at the drain of the drive transistor onto theorganic light emitting diode in the light emission stage so that theorganic light emitting diode emits light with the difference in voltagebetween a first power supply signal and a second power supply signal.

The pixel circuit according to the embodiment of the present inventionmay be embodied in a circuit structure illustrated in FIG. 2 or may beembodied in a circuit structure illustrated in FIG. 3, wherein when apixel circuit according to the embodiment of the present invention isembodied in the circuit structure illustrated in FIG. 2, all of atransistor in the signal loading component 11, a transistor in thecompensation component 12, a transistor in the mirror component 13, andthe drive transistor Td, in the pixel circuit are n-type transistors;and when a pixel circuit according to an embodiment of the presentinvention is embodied in the circuit structure illustrated in FIG. 3,all of a transistor in the signal loading component 11, a transistor inthe compensation component 12, a transistor in the mirror component 13,and the drive transistor Td, in the pixel circuit are p-typetransistors.

When the pixel circuit according to the embodiment of the presentinvention is embodied in the circuit structure illustrated in FIG. 2,the image data signal Data is received at a first end 111 of the signalloading component 11, a first control signal Ctr1 is received at asecond end 112 of the signal loading component 11, and a third end 113of the signal loading component 11 is connected with the gate of thedrive transistor Td; a second control signal Ctr2 is received at a firstend 121 of the compensation component 12, a second end 122 of thecompensation component 12 is connected with the gate of the drivetransistor Td, and a third end 123 of the compensation component 12 isconnected with the source of the drive transistor Td; a third controlsignal Ctr3 is received at a first end 131 of the mirror component 13, asecond end 132 of the mirror component 13 is connected with the sourceof the drive transistor Td, the second power supply signal VD2 isreceived at a third end 133 of the mirror component 132, and a fourthend 134 of the mirror component 13 is connected with the cathode of theOrganic Light Emitting Diode (OLED); the first power supply signal VD1is received at the anode of the Organic Light Emitting Diode (OLED), andthe first power supply signal VD1 is received at the drain of the drivetransistor Td; one end of the storage capacitor Cs is connected with thedrain of the drive transistor Td, and the other end of the storagecapacitor Cs is connected with the gate of the drive transistor Td; andthe signal loading component 11 is configured to connect the first end111 of the signal loading component 11 to the third end 113 of thesignal loading component 11 in the data transmission stage so that thereceived image data signal Data is transmitted to the gate of the drivetransistor Td in the data transmission stage, the compensation component12 is configured to connect the second end 122 of the compensationcomponent 12 to the third end 123 of the compensation component 12 inthe threshold voltage compensation stage so as to generate the drivesignal from the image data signal stored in the storage capacitor, andthe mirror component 13 is configured to connect the second end 132 ofthe mirror component 13 to the third end 133 of the mirror component 13in the light emission stage.

When the pixel circuit according to the embodiment of the presentinvention is embodied in the circuit structure illustrated in FIG. 2,the voltage at the gate of the drive transistor Td is the voltage Vdataof the image data signal Data at the end of the data transmission stage,and the voltage at the gate of the drive transistor Td is Vdata+Vth atthe end of the threshold voltage compensation stage; and the drivetransistor Td in FIG. 2 is an n-type transistor, so the thresholdvoltage Vth of the drive transistor Td is above zero. The drivetransistor Td operates in a saturated region in the light emission stageso that the current at the drain thereof is generated from thedifference in voltage between the gate and drain of the drive transistorTd, so the value of the current at the drain Id of the drive transistorTd may be calculated via the equation of a current characteristic of atransistor operating in a saturated region: I_(d)=½k(V_(gs)−Vth)²,wherein k is dependent upon a structural parameter of the drivetransistor Td, Vth represents the threshold voltage of the drivetransistor Td, Vgs represents the difference between the voltage Vg atthe gate of the drive transistor Td and the voltage Vs at the source ofthe drive transistor Td, that is, Vgs=Vg−Vs=Vdata+Vth−Vd1, and Vd1represents the voltage of the first power supply signal VD1, so thecurrent at the drain Id of the drive transistor Td isI_(d)=½k(Vdata−Vd1)². It can be seen that the current at the drain I_(d)of the drive transistor Td will not vary with the threshold voltage Vthof the drive transistor Td, and the mirror component will mirror thecurrent at the drain I_(d) of the drive transistor Td onto the organiclight emitting diode to drive the organic light emitting diode emitlight, that is, the threshold voltage Vth of the drive transistor Tdwill have no influence on the drive current flowing through the organiclight emitting diode, thus preventing the brightness of the organiclight emitting diode from varying over its operating period of time.

When the pixel circuit according to the embodiment of the presentinvention is embodied in the circuit structure illustrated in FIG. 3,the image data signal Data is received at a fourth end 114 of the signalloading component 11, a fourth control signal Ctr4 is received at afifth end 115 of the signal loading component 11, a sixth end 116 of thesignal loading component 11 is connected with one end of the storagecapacitor Cs, a fifth control signal Ctr5 is received at a seventh end117 of the signal loading component 11, an eighth end 118 of the signalloading component 11 is connected with the drain of the drive transistorTd, and the other end of the storage capacitor Cs is connected with thegate of the drive transistor Td; a sixth control signal Ctr6 is receivedat a first end 121 of the compensation component 12, a second end 122 ofthe compensation component 12 is connected with the gate of the drivetransistor Td, and a third end 123 of the compensation component 12 isconnected with the source of the drive transistor Td; the fifth controlsignal Ctr5 is received at a first end 131 of the mirror component 13, asecond end 132 of the mirror component 13 is connected with the sourceof the drive transistor Td, the second power supply signal VD2 isreceived at a third end 133 of the mirror component 132, and a fourthend 134 of the mirror component 13 is connected with the cathode of theOrganic Light Emitting Diode (OLED); the first power supply signal VD1is received at the anode of the Organic Light Emitting Diode (OLED), andthe first power supply signal VD1 is received at the drain of the drivetransistor Td; and the signal loading component 11 is configured toconnect the fourth end 114 of the signal loading component 11 to thesixth end 116 of the signal loading component 11 in the datatransmission stage and to disconnect the fourth end 114 of the signalloading component 11 from the sixth end 116 of the signal loadingcomponent 11 in both the threshold voltage compensation stage and thelight emission stage; and to disconnect the sixth end 116 of the signalloading component 11 from the eighth end 118 of the signal loadingcomponent 11 in both the data transmission stage and the thresholdvoltage compensation stage, and to connect the sixth end 116 of thesignal loading component 11 to the eighth end 118 of the signal loadingcomponent 11 in the light emission stage; the compensation component 12is configured to connect the second end 122 of the compensationcomponent 12 to the third end 123 of the compensation component 12 inthe threshold voltage compensation stage so as to generate the drivesignal from the image data signal stored in the storage capacitor Cs;and the mirror component 13 is configured to connect the second end 132of the mirror component 13 to the third end 133 of the mirror component13 in the light emission stage.

The signal loading component 11 connects the fourth end 114 of thesignal loading component 11 to the sixth end 116 of the signal loadingcomponent 11, and disconnects the sixth end 116 of the signal loadingcomponent 11 from the eight end 118 of the signal loading component 11in the data transmission stage, so that in the data transmission stage,the signal loading component 11 may transmit the received image datasignal Data to one end of the storage capacitor Cs, i.e., the end of thestorage capacitor Cs connected with the sixth end 116 of the signalloading component 11, and since the end of the storage capacitor Csconnected with the gate of the drive transistor Td floats, the variationin voltage at the end of the storage capacitor Cs connected with thesixth end 116 of the signal loading component 11 may be coupled to theend of the storage capacitor Cs connected with the gate of the drivetransistor Td, so the signal loading component 11 may transmit thereceived image data signal Data to the gate of the drive transistor Tdin the data transmission stage.

When the pixel circuit according to the embodiment of the presentinvention is embodied in the circuit structure illustrated in FIG. 3,the voltage at the gate of the drive transistor Td is the voltage Vdataof the image data signal Data at the end of the data transmission stage,and the voltage at the gate of the drive transistor Td is Vdata+Vth atthe end of the threshold voltage compensation stage; and the drivetransistor Td in FIG. 3 is a p-type transistor, so the threshold voltageVth of the drive transistor Td is below zero. In the light emissionstage, the sixth end 116 of the signal loading component 11 is connectedwith the eighth end 118 of the signal loading component 11, and thedrive transistor Td operates in a saturated region, so that the currentat the drain of the drive transistor Td is generated from the differencein voltage between the gate and source of the drive transistor Td, sothe value of the current at the drain I_(d) of the drive transistor Tdmay be calculated via the equation of a current characteristic of atransistor operating in a saturated region: I_(d)=½k(V_(gs)−Vth)²,wherein k is dependent upon a structural parameter of the drivetransistor Td, Vth represents the threshold voltage of the drivetransistor Td, V_(gs) represents the difference between the voltageV_(g) at the gate of the drive transistor Td and the voltage V_(s) atthe source of the drive transistor Td, that is,V_(gs)=V_(g)−V_(s)=Vdata+Vth−Vd1, and Vd1 represents the voltage of thefirst power supply signal VD1, so the current at the drain I_(d) of thedrive transistor Td is I_(d)=½k(Vdata−Vd1)². It can be seen that thecurrent at the drain I_(d) of the drive transistor Td will not vary withthe threshold voltage Vth of the drive transistor Td, and the mirrorcomponent will mirror the current at the drain I_(d) of the drivetransistor Td onto the organic light emitting diode to drive the organiclight emitting diode emit light, that is, the threshold voltage Vth ofthe drive transistor Td will have no influence on the drive currentflowing through the organic light emitting diode, thus preventing thebrightness of the organic light emitting diode from varying over itsoperating period of time.

Furthermore, when all of transistors in the signal loading component,the compensation component and the mirror component in the pixel circuitaccording to the embodiment of the present invention are n-typetransistors, and the drive transistor is an n-type transistor, the pixelcircuit according to the embodiment of the present invention is asillustrated in any one of FIG. 4 to FIG. 7, wherein the signal loadingcomponent 11 includes a first transistor T1; a first terminal of thefirst transistor T1 is the first end 111 of the signal loading component11, the gate of the first transistor T1 is the second end 112 of thesignal loading component 11, the first control signal Ctr1 is receivedat the gate of the first transistor T1, and a second terminal of thefirst transistor T1 is the third end 113 of the signal loading component11; and the first transistor T1 is turned on in the data transmissionstage and turned off in the threshold voltage compensation stage and thelight emission stage.

As illustrated in FIG. 4 or FIG. 6, when all the transistors in thesignal loading component, the compensation component and the mirrorcomponent in the pixel circuit according to the embodiment of thepresent invention are n-type transistors, and the drive transistor is ann-type transistor, the compensation component 12 in the pixel circuitaccording to the embodiment of the present invention includes a fourthtransistor T4 and a fifth transistor T5, wherein the gate of the fourthtransistor T4 is the first end 121 of the compensation component 12, thesecond control signal Ctr2 is received at the first end 121, the firstterminal of the fourth transistor T4 is the second end 122 of thecompensation component 12, and the second terminal of the fourthtransistor T4 is a first terminal of the fifth transistor T5; the gateof the fifth transistor T5 is the first end 121 of the compensationcomponent 12, the second control signal Ctr2 is received at the firstend 121, and a second terminal of the fifth transistor T5 is the thirdend 123 of the compensation component 12; and both the fourth transistorT4 and the fifth transistor T5 are configured to be turned on in thethreshold voltage compensation stage and to be turned off in the datatransmission stage and the light emission stage.

Since there is a gate-source parasitic capacitance and a gate-drainparasitic capacitance of a transistor per se and there is also aparasitic capacitance of overlapping line segments in the pixel circuit,when the respective control signals change, a potential at the gate ofthe drive transistor Td may change due to a coupling effect of theparasitic capacitance, thus degrading the effect of compensation in thethreshold voltage compensation stage.

Thus, preferably as illustrated in FIG. 5 or FIG. 7, when all thetransistors in the signal loading component, the compensation componentand the mirror component in the pixel circuit according to theembodiment of the present invention are n-type transistors, and thedrive transistor is an n-type transistor, the compensation component 12in the pixel circuit according to the embodiment of the presentinvention further includes a sixth transistor T6 and a first capacitorC1, wherein both a first terminal of the sixth transistor T6 and one endof the first capacitor C1 are connected with the second terminal of thefourth transistor T4; the second power supply signal VD2 is received atthe other end of the first capacitor C1; a signal received at the gateof the sixth transistor T6 is the same as the signal received at thefirst end 131 of the mirror component 13, that is, the third controlsignal Ctr3 is received at the gate of the sixth transistor T6, and asecond terminal of the sixth transistor T6 is connected with the gate ofthe drive transistor Td; the sixth transistor T6 is turned on in thelight emission stage and turned off in both the data transmission stageand the threshold voltage compensation stage; and the first capacitor C1is charged in the threshold voltage compensation stage so that the drivetransistor Td generates the drive signal from the stored image datasignal.

After the sixth transistor T6 and the first capacitor C1 are added tothe compensation component, in the threshold voltage compensation stage,the second power supply signal VD2 is received at one end of the firstcapacitor C1, and the voltage of the second power supply signal VD2 issubstantially stable, so that the potential at the gate of the drivetransistor Td may be locked effectively, thus, the potential at the gateof the drive transistor Td will not be easily changed with the variationof the respective control signals, and further make the compensatedpotential at the gate of the drive transistor Td be closer to a presetpotential, i.e., Vdata+Vth.

Furthermore as illustrated in FIG. 4 or FIG. 5, when all the transistorsin the signal loading component, the compensation component and themirror component in the pixel circuit according to the embodiment of thepresent invention are n-type transistors, and the drive transistor is ann-type transistor, the mirror component in the pixel circuit accordingto the embodiment of the present invention includes a seventh transistorT7, an eighth transistor T8 and a ninth transistor T9, wherein a firstterminal of the seventh transistor T7 is the second end 132 of themirror component 13, the gate of the seventh transistor T7 is the firstend 131 of the mirror component 13, the third control signal Ctr3 isreceived at the first end 131, and a second terminal of the seventhtransistor T7 is connected respectively with a first terminal of theeighth transistor T8, the gate of the eighth transistor T8 and the gateof the ninth transistor T9; a second terminal of the eighth transistorT8 is the third end 133 of the mirror component 13; and a first terminalof the ninth transistor T9 is the fourth end 134 of the mirror component13, and a second terminal of the ninth transistor T9 is the third end133 of the mirror component 13.

At this time, after the seventh transistor T7 is turned on, the currentflowing through the eighth transistor T8 is the same as the currentflowing through the ninth transistor T9 when the parameter of the eighthtransistor T8 is the same as that of the ninth transistor T9, so themirror component may mirror the current at the drain of the drivetransistor Td onto the organic light emitting diode to drive the OrganicLight Emitting Diode (OLED) to emit light.

Preferably, when all the transistors in the signal loading component,the compensation component and the mirror component in the pixel circuitaccording to the embodiment of the present invention are n-typetransistors, and the drive transistor is an n-type transistor, themirror component in the pixel circuit according to the embodiment of thepresent invention is further configured to perform negative feedbackcontrol on the current flowing through the organic light emitting diodeto stabilize the current flowing through the organic light emittingdiode.

At this time, as illustrated in FIG. 6 or FIG. 7, the mirror componentin the pixel circuit according to the embodiment of the presentinvention includes a tenth transistor T10, an eleventh transistor T11, atwelfth transistor T12 and a thirteenth transistor T13, wherein a firstterminal of the tenth transistor T10 is the second end 132 of the mirrorcomponent 13, the gate of the tenth transistor T10 is the first end 131of the mirror component 13, the third control signal Ctr3 is received atthe first end 131, and a second terminal of the tenth transistor T10 isconnected respectively with a first terminal of the eleventh transistorT11, the gate of the eleventh transistor T11, the gate of the twelfthtransistor T12 and the gate of the thirteenth transistor T13; a secondterminal of the eleventh transistor T11 is the third end 133 of themirror component 13; and a first terminal of the twelfth transistor T12is connected with a first terminal of the thirteenth transistor T13, asecond terminal of the twelfth transistor T12 is the third end 133 ofthe mirror component 13, and a second terminal of the thirteenthtransistor T13 is the fourth end 134 of the mirror component 13.

In FIG. 6 or FIG. 7, when the tenth transistor T10 is turned on, theeleventh transistor T11 operates in a linear region as an activeresistor, and when the current at the drain I_(d) of the drivetransistor Td is constant, the drain-source current I_(ds10) of thetenth transistor T10 is constant, and the drain-source current I_(ds11)of the eleventh transistor T11 is equal to I_(ds10), and the eleventhtransistor T11 is an active resistor, so the drain-source difference involtage V_(ds10) of the eleventh transistor T11V_(ds11)=V_(g113)+V_(ds12) is constant, wherein V_(g113) represents thedifference in voltage between the gate of the thirteen transistor T13and the first terminal of the thirteen transistor T13, and V_(ds12)represents the source-drain difference in voltage of the twelfthtransistor T12; and if the current flowing through the Organic LightEmitting Diode (OLED) raises, then the current flowing through thesource and the drain of the thirteen transistor T13 raises, and thecurrent flowing through the source and the drain of the twelfthtransistor T12 raises, and when the current flowing through the sourceand the drain of the twelfth transistor T12 raises, the source-draindifference in voltage V_(ds12) across the twelfth transistor T12 raises,and since the drain-source difference in voltage V_(ds11) of theeleventh transistor T11 is constant, the difference in voltage V_(g113)between the gate of the thirteen transistor T13 and the first terminalof the thirteen transistor T13 drops, and according to thecharacteristic of a transistor operating in a saturated region, when thedifference in voltage between the gate of the thirteen transistor T13and the first terminal of the thirteen transistor T13 is above thethreshold voltage of the thirteen transistor T13, the current on thesecond terminal of the thirteen transistor T13 drops with the droppingdifference in voltage V_(g113) between the gate of the thirteentransistor T13 and the first terminal of the thirteen transistor T13,that is, the current flowing through the Organic Light Emitting Diode(OLED) also drops. Similarly, if the current flowing through the OrganicLight Emitting Diode (OLED) drops, then the current flowing through thesource and the drain of the thirteen transistor T13 drops, and thecurrent flowing through the source and the drain of the twelfthtransistor T12 drops, and when the current flowing through the sourceand the drain of the twelfth transistor T12 drops, the source-draindifference in voltage V_(ds12) across the twelfth transistor T12 drops,and since the drain-source difference in voltage V_(ds11) of theeleventh transistor T11 is constant, the difference in voltage V_(g113)between the gate of the thirteen transistor T13 and the first terminalof the thirteen transistor T13 raises, and as per the characteristic ofa transistor operating in a saturated region, when the difference involtage between the gate of the thirteen transistor T13 and the firstterminal of the thirteen transistor T13 is above the threshold voltageof the thirteen transistor T13, the current on the second terminal ofthe thirteen transistor T13 raises with the raising difference involtage V_(g113) between the gate of the thirteen transistor T13 and thefirst terminal of the thirteen transistor T13, that is, the currentflowing through the Organic Light Emitting Diode (OLED) also raises.Thus the mirror component 13 in FIG. 6 or FIG. 7 may stabilize thecurrent flowing through the Organic Light Emitting Diode (OLED).

The first terminal of any one of the eleventh transistor T11, thetwelfth transistor T12 and the thirteenth transistor T13 in FIG. 6 orFIG. 7 may be the source (or the drain) of the transistor, and thesecond terminal of the transistor may be the drain (or the source) ofthe transistor. If the source of the transistor is the first pole, thenthe drain of the transistor is the second pole; and if the drain of thetransistor is the first pole, then the source of the transistor is thesecond pole.

All the first transistor T1, the fourth transistor T4, the fifthtransistor T5, the sixth transistor T6, the seventh transistor T7, theeighth transistor T8, the ninth transistor T9, the tenth transistor T10,the eleventh transistor T11, the twelfth transistor T12, the thirteenthtransistor T13 and the drive transistor Td in the pixel circuitillustrated in FIG. 4, FIG. 5, FIG. 6 and FIG. 7 are n-type transistors.

FIG. 8 illustrates an operating timing of the pixel circuit illustratedin FIG. 4, FIG. 5, FIG. 6 and FIG. 7, wherein in the data transmissionstage t1, the first control signal Ctr1 is at a high level, so the firsttransistor T1 is turned on, so that the image data signal Data istransmitted to the gate of the drive transistor Td and stored in thestorage capacitor Cs, and the voltage at the first node N1 is Vdata,i.e., the voltage of the image data signal Data; the second controlsignal Ctr2 is at a low level, so both the fourth transistor T4 and thefifth transistor T5 are turned off; and the third control signal Ctr3 isat a low level, so the sixth transistor T6 in FIG. 5 and FIG. 7 isturned off, the seventh transistor T7 in FIG. 4 and FIG. 5 is turnedoff, and the tenth transistor T10 in FIG. 6 and FIG. 7 is turned off.

In the threshold voltage compensation stage t2, the first control signalCtr1 is at a low level, so the first transistor T1 is turned off; thesecond control signal Ctr2 is at a high level, so both the fourthtransistor T4 and the fifth transistor T5 are turned on, so that thegate of the drive transistor Td is connected to the source of the drivetransistor Td, and the voltage at the first node N1, the voltage at thesecond node N2 and the voltage at the third node N3 are equal and areall equal to Vdata+Vth, wherein Vth represents the threshold voltage ofthe drive transistor, and the third control signal Ctr3 is at a lowlevel, so the sixth transistor T6 in FIG. 5 and FIG. 7 is turned off,the seventh transistor T7 in FIG. 4 and FIG. 5 is turned off, and thetenth transistor T10 in FIG. 6 and FIG. 7 is turned off.

In the light emission stage t3, the first control signal Ctr1 is at alow level, so the first transistor T1 is turned off; the second controlsignal Ctr2 is at a low level, so both the fourth transistor T4 and thefifth transistor T5 are turned off; and the third control signal Ctr3 isat a high level, so the seventh transistor T7 in FIG. 4 and FIG. 5 isturned on, the tenth transistor T10 in FIG. 6 and FIG. 7 is turned on,the mirror component 13 starts to operate, and the sixth transistor T6in FIG. 5 and FIG. 7 is turned on, so that the Organic Light EmittingDiode (OLED) emits light.

Of course, the operating timing of the pixel circuit illustrated in FIG.4, FIG. 5, FIG. 6 and FIG. 7 may alternatively be as illustrated in FIG.9, wherein the first control signal Ctr1 will not be changed to a highlevel until the third control signal Ctr3 is changed to a low level, sothat the Organic Light Emitting Diode (OLED) may be ensured not totransmit the current frame of image data signal to the gate of the drivetransistor Td until it stops from emitting light. In FIG. 9, the firstcontrol signal Ctr1 will not be changed to a high level until the imagedata signal becomes the current frame of image data, so that the currentframe of image data signal may be ensured not to be transmitted to thegate of the drive transistor Td until it becomes stable; moreover, thesecond control signal Ctr2 will not be changed to a high level until thefirst control signal Ctr1 is changed to a low level, so that thresholdvoltage compensation may be ensured not to be performed until the firsttransistor T1 is turned off, and thus the first transistor T1 may beprevented from transmitting the signal to the gate of the drivetransistor Td during threshold voltage compensation; and lastly, thethird control signal Ctr3 will not be changed to a high level until thesecond control signal Ctr2 is changed to a low level, so that the gateof the drive transistor Td may be ensured to be disconnected from thesource of the drive transistor Td when the Organic Light Emitting Diode(OLED) is driven to emit light.

Furthermore, when all the transistors in the signal loading component,the compensation component and the mirror component in the pixel circuitaccording to the embodiment of the present invention are p-typetransistors, and the drive transistor is a p-type transistor, the pixelcircuit according to the embodiment of the present invention is asillustrated in any one of FIG. 10 to FIG. 13, and the signal loadingcomponent 11 includes a second transistor T2 and a third transistor T3,wherein a first terminal of the second transistor T2 is the fourth end114 of the signal loading component 11, the gate of the secondtransistor T2 is the fifth end 115 of the signal loading component 11,the fourth control signal Ctr4 is received at the fifth end 115, and thesecond terminal of the second transistor T2 is the sixth end 116 of thesignal loading component 11; and a first terminal of the thirdtransistor T3 is the sixth end 116 of the signal loading component 11,the gate of the third transistor T3 is the seventh end 117 of the signalloading component 11, the fifth control signal Ctr5 is received at theseventh end 117, and a second terminal of the third transistor T3 is theeighth end 118 of the signal loading component 11; and the secondtransistor T2 is turned on in the data transmission stage and turned offin both the threshold voltage compensation stage and the light emissionstage, and the third transistor T3 is turned on in the light emissionstage and turned off in the data transmission stage and the thresholdvoltage compensation stage.

The second transistor T2 is turned on and the third transistor T3 isturned off in the data transmission stage, so in the data transmissionstage, the second transistor T2 may transmit the received image datasignal Data to one end of the storage capacitor Cs, i.e., the end of thestorage capacitor Cs connected with the second terminal of the secondtransistor T2, and since the end of the storage capacitor Cs connectedwith the gate of the drive transistor Td floats, according to thecoupling behavior of a capacitor, the variation in voltage at the end ofthe storage capacitor Cs connected with the second terminal of thesecond transistor T2 may be coupled to the end of the storage capacitorCs connected with the gate of the drive transistor Td, so that thesignal loading component 11 may transmit the received image data signalData to the gate of the drive transistor Td in the data transmissionstage.

As illustrated in FIG. 10 or FIG. 12, when all the transistors in thesignal loading component, the compensation component and the mirrorcomponent in the pixel circuit according to the embodiment of thepresent invention are p-type transistors, and the drive transistor is ap-type transistor, the compensation component 12 in the pixel circuitaccording to the embodiment of the present invention includes a fourthtransistor T4 and a fifth transistor T5, wherein a gate of the fourthtransistor T4 is the first end 121 of the compensation component 12, andthe sixth control signal Ctr6 is received at the first end 121, a firstterminal of the fourth transistor T4 is the second end 122 of thecompensation component 12, and a second terminal of the fourthtransistor T4 is a first terminal of the fifth transistor T5; the gateof the fifth transistor T5 is the first end 121 of the compensationcomponent 12, and the sixth control signal Ctr6 is received at the firstend 121, and a second terminal of the fifth transistor T5 is the thirdend 123 of the compensation component 12; and both the fourth transistorT4 and the fifth transistor T5 are configured to be turned on in thethreshold voltage compensation stage and turned off in the datatransmission stage and the light emission stage.

Since there is a gate-source parasitic capacitance and a gate-drainparasitic capacitance of a transistor per se and there is also aparasitic capacitance of overlapping line segments in the pixel circuit,when the respective control signals change, a potential at the gate ofthe drive transistor Td may change due to a coupling effect of thecapacitance, thus degrading the effect of compensation in the thresholdvoltage compensation stage.

Thus preferably as illustrated in FIG. 11 or FIG. 13, when all thetransistors in the signal loading component, the compensation componentand the mirror component in the pixel circuit according to theembodiment of the present invention are p-type transistors, and thedrive transistor is a p-type transistor, the compensation component 12in the pixel circuit according to the embodiment of the presentinvention further includes a sixth transistor T6 and a first capacitorC1, wherein both a first terminal of the sixth transistor T6 and one endof the first capacitor C1 are connected with the second terminal of thefourth transistor T4; the second power supply signal VD2 is received atthe other end of the first capacitor C1; a signal received at the gateof the sixth transistor T6 is the same as the signal received at thefirst end 131 of the mirror component 13, that is, the fifth controlsignal Ctr5 is received at the gate of the sixth transistor T6, and asecond terminal of the sixth transistor T6 is connected with the gate ofthe drive transistor Td; the sixth transistor T6 is turned on in thelight emission stage and turned off in both the data transmission stageand the threshold voltage compensation stage, and the first capacitor C1is charged in the threshold voltage compensation stage so that the drivetransistor Td generates the drive signal from the stored image datasignal.

After the sixth transistor T6 and the first capacitor C1 are added tothe compensation component, in the threshold voltage compensation stage,the second power supply signal VD2 is received at one end of the firstcapacitor C1, and the voltage of the second power supply signal VD2 issubstantially stable, so that the potential at the gate of the drivetransistor Td may be locked effectively, thus the potential at the gateof the drive transistor Td will not be easily changed with the variationof the respective control signals, and further make the compensatedpotential at the gate of the drive transistor Td be closer to a presetpotential, i.e., Vdata+Vth; and when the light emission stage starts,that is, the turned-off third transistor is turned on, the firstcapacitor C1 may lock effectively the potential at the gate of the drivetransistor Td so that it will not vary with the varying voltage at theend of the storage capacitor Cs connected with the second terminal ofthe second transistor T2.

Furthermore as illustrated in FIG. 10 or FIG. 11, when all thetransistors in the signal loading component, the compensation componentand the mirror component in the pixel circuit according to theembodiment of the present invention are p-type transistors, and thedrive transistor is a p-type transistor, the mirror component in thepixel circuit according to the embodiment of the present inventionincludes a seventh transistor T7, an eighth transistor T8 and a ninthtransistor T9, wherein a first terminal of the seventh transistor T7 isthe second end 132 of the mirror component 13, the gate of the seventhtransistor T7 is the first end 131 of the mirror component 13, and thefifth control signal Ctr5 is received at the first end 131, and a secondterminal of the seventh transistor T7 is connected respectively with afirst terminal of the eighth transistor T8, the gate of the eighthtransistor T8 and the gate of the ninth transistor T9; a second terminalof the eighth transistor T8 is the third end 133 of the mirror component13; and a first terminal of the ninth transistor T9 is the fourth end134 of the mirror component 13, and a second terminal of the ninthtransistor T9 is the third end 133 of the mirror component 13.

At this time, after the seventh transistor T7 is turned on, the currentflowing through the eighth transistor T8 is the same as the currentflowing through the ninth transistor T9 when the parameter of the eighthtransistor T8 is the same as that of the ninth transistor T9, so themirror component may mirror the current at the drain of the drivetransistor Td onto the organic light emitting diode so as to drive theOrganic Light Emitting Diode (OLED) to emit light.

Preferably when all the transistors in the signal loading component, thecompensation component and the mirror component in the pixel circuitaccording to the embodiment of the present invention are p-typetransistors, and the drive transistor is a p-type transistor, the mirrorcomponent in the pixel circuit according to the embodiment of thepresent invention is further configured to perform negative feedbackcontrol on the current flowing through the organic light emitting diodeto stabilize the current flowing through the organic light emittingdiode.

At this time, as illustrated in FIG. 12 or FIG. 13, the mirror componentin the pixel circuit according to the embodiment of the presentinvention includes a tenth transistor T10, an eleventh transistor T11, atwelfth transistor T12 and a thirteenth transistor T13, wherein a firstterminal of the tenth transistor T10 is the second end 132 of the mirrorcomponent 13, the gate of the tenth transistor T10 is the first end 131of the mirror component 13, and the fifth control signal Ctr5 isreceived at the first end 131, and a second terminal of the tenthtransistor T10 is connected respectively with a first terminal of theeleventh transistor T11, the gate of the eleventh transistor T11, thegate of the twelfth transistor T12 and the gate of the thirteenthtransistor T13; a second terminal of the eleventh transistor T11 is thethird end 133 of the mirror component 13; and a first terminal of thetwelfth transistor T12 is connected with a first terminal of thethirteenth transistor T13, a second terminal of the twelfth transistorT12 is the third end 133 of the mirror component 13, and a secondterminal of the thirteenth transistor T13 is the fourth end 134 of themirror component 13.

The mirror component 13 in FIG. 12 or FIG. 13 stabilizes the currentflowing through the Organic Light Emitting Diode (OLED) under the sameprinciple as the principle under which the mirror component 13 in FIG. 6or FIG. 7 stabilizes the current flowing through the Organic LightEmitting Diode (OLED), and there is no need to repeat herein.

The first terminal of any one of the eleventh transistor T11, thetwelfth transistor T12 and the thirteenth transistor T13 in FIG. 12 orFIG. 13 may be the source (or the drain) of the transistor, and thesecond terminal of the transistor may be the drain (or the source) ofthe transistor. If the source of the transistor is the first pole, thenthe drain of the transistor is the second pole; and if the drain of thetransistor is the first pole, then the source of the transistor is thesecond pole.

All the second transistor T2, the third transistor T3, the fourthtransistor T4, the fifth transistor T5, the sixth transistor T6, theseventh transistor T7, the eighth transistor T8, the ninth transistorT9, the tenth transistor T10, the eleventh transistor T11, the twelfthtransistor T12, the thirteenth transistor T13 and the drive transistorTd in the pixel circuit illustrated in FIG. 10, FIG. 11, FIG. 12 andFIG. 13 are p-type transistors.

FIG. 14 illustrates an operating timing of the pixel circuit illustratedin FIG. 10, FIG. 11, FIG. 12 and FIG. 13, wherein in the datatransmission stage t1, since the fourth control signal Ctr4 is at a lowlevel, so the second transistor T2 is turned on, and since the fifthcontrol signal Ctr5 is at a high level, so the third transistor T3 isturned off, so that the image data signal Data may be transmitted to thegate of the drive transistor Td through the storage capacitor Cs, andstored in the storage capacitor Cs, and the voltage at the first node N1is Vdata, i.e., the voltage of the image data signal Data; the sixthcontrol signal Ctr6 is at a high level, so both the fourth transistor T4and the fifth transistor T5 are turned off; and the fifth control signalCtr5 is at a high level, so the sixth transistor T6 in FIG. 11 and FIG.13 is turned off, the seventh transistor T7 in FIG. 10 and FIG. 11 isturned off, and the tenth transistor T10 in FIG. 12 and FIG. 13 isturned off.

In the threshold voltage compensation stage t2, the fourth controlsignal Ctr4 is at a high level, so the second transistor T2 is turnedoff, and the fifth control signal Ctr5 is at a high level, so the thirdtransistor T3 is turned off; the sixth control signal Ctr6 is at a highlevel, so both the fourth transistor T4 and the fifth transistor T5 areturned on so that the gate of the drive transistor Td is connected tothe source of the drive transistor Td, and the voltage at the fourthnode N4, the voltage at the fifth node N5 and the voltage at the sixthnode N6 are equal and are all equal to Vdata+Vth, wherein Vth representsthe threshold voltage of the drive transistor; and the fifth controlsignal Ctr5 is at a high level, so the sixth transistor T6 in FIG. 11and FIG. 13 is turned off, the seventh transistor T7 in FIG. 10 and FIG.11 is turned off, and the tenth transistor T10 in FIG. 12 and FIG. 13 isturned off.

In the light emission stage t3, the fourth control signal Ctr4 is at ahigh level, so the second transistor T2 is turned off, and the fifthcontrol signal Ctr5 is at a low level, so the third transistor T3 isturned on, and the one end of the storage capacitor Cs does not floatany longer but the first power supply signal VD1 is received at thatend; the sixth control signal Ctr6 is at a high level, so both thefourth transistor T4 and the fifth transistor T5 are turned off; and thefifth control signal Ctr5 is at a low level, so the sixth transistor T6in FIG. 11 and FIG. 13 is turned on, the seventh transistor T7 in FIG.10 and FIG. 11 is turned on, and the tenth transistor T10 in FIG. 12 andFIG. 13 is turned on, so that the Organic Light Emitting Diode (OLED)emits light.

Of course, the operating timing of the pixel circuit illustrated in FIG.10, FIG. 11, FIG. 12 and FIG. 13 may alternatively be as illustrated inFIG. 15, wherein the fourth control signal Ctr4 will not be changed to alow level until the fifth control signal Ctr5 is changed to a high levelso that the Organic Light Emitting Diode (OLED) may be ensured not totransmit the current frame of image data signal to the gate of the drivetransistor Td until it stops from emitting light; in FIG. 15, the fourthcontrol signal Ctr4 will not be changed to a high level until the imagedata signal becomes the current frame of image data, so that the currentframe of image data signal may be ensured not to be transmitted to thegate of the drive transistor Td until it becomes stable; moreover, thesixth control signal Ctr6 will not be changed to a low level until thefourth control signal Ctr4 is changed to a high level, so that thresholdvoltage compensation may be ensured not to be performed until the secondtransistor T2 is turned off, and thus the second transistor T2 may beavoided from transmitting the signal to the gate of the drive transistorTd during threshold voltage compensation; and lastly, the fifth controlsignal Ctr5 will not be changed to a low level until the sixth controlsignal Ctr6 is changed to a high level, so that the gate of the drivetransistor Td may be ensured to be disconnected from the source of thedrive transistor Td when the Organic Light Emitting Diode (OLED) isdriven to emit light.

An embodiment of the present invention further provides a pixel circuitfor driving an organic light emitting diode, the pixel circuit includinga first transistor, a second transistor, a third transistor, a fourthtransistor, a fifth transistor, a sixth transistor, a drive transistorand a storage capacitor, wherein the first transistor includes a firstterminal at which an image data signal is received, the gate at which afirst control signal is received, and a second terminal connectedrespectively with the gate of the drive transistor and one end of thestorage capacitor; the second transistor includes a first terminalconnected with the gate of the drive transistor, the gate at which asecond control signal is received, and a second terminal connected witha first terminal of the third transistor; the third transistor includesthe gate at which the second control signal is received, and a secondterminal connected with the source of the drive transistor; the drivetransistor includes the drain at which a first power supply signal isreceived; the fourth transistor includes a first terminal connected withthe source of the drive transistor, the gate at which the third controlsignal is received, and a second terminal connected respectively with afirst terminal of the fifth transistor, the gate of the fifth transistorand the gate of the sixth transistor, the fifth transistor includes asecond terminal at which a second power supply signal is received; thesixth transistor includes a first terminal connected with the cathode ofthe organic light emitting diode, and a second terminal at which asecond power supply signal is received; and the storage capacitorincludes the other end at which the first power supply signal isreceived.

At this time the first transistor is T1 in FIG. 4, the second transistoris T4 in FIG. 4, the third transistor is T5 in FIG. 4, the drivetransistor is Td in FIG. 4, the fourth transistor is T7 in FIG. 4, thefifth transistor is T8 in FIG. 4, the sixth transistor is T9 in FIG. 4,the storage capacitor is Cs in FIG. 4, and the organic light emittingdiode is the OLED in FIG. 4.

Optionally, the pixel circuit according to the embodiment of the presentinvention further includes a seventh transistor and a first capacitor,wherein the seventh transistor includes a first terminal connected withthe second terminal of the second transistor, a gate at which the thirdcontrol signal is received, and a second terminal connected with thegate of the drive transistor, and the first capacitor includes one endconnected with the second terminal of the second transistor, and theother end at which the second power supply signal is received.

At this time, the seventh transistor is T6 in FIG. 5, and the firstcapacitor is C1 in FIG. 5.

Optionally, the pixel circuit according to the embodiment of the presentinvention further includes an eighth transistor, wherein the firstterminal of the sixth transistor is connected with the cathode of theorganic light emitting diode through the eighth transistor, and the gateof the eighth transistor is connected with the second terminal of thefourth transistor.

At this time, the fourth transistor is T10 in FIG. 6 or FIG. 7, thefifth transistor is T11 in FIG. 6 or FIG. 7, the sixth transistor is T12in FIG. 6 or FIG. 7, and the eighth transistor is T13 in FIG. 6 or FIG.7.

An embodiment of the present invention further provides a pixel circuitfor driving an organic light emitting diode, the pixel circuit includinga first transistor, a second transistor, a third transistor, a fourthtransistor, a fifth transistor, a sixth transistor, a seventhtransistor, a drive transistor and a storage capacitor.

The first transistor includes a first terminal at which an image datasignal is received, the gate at which a fourth control signal isreceived, and a second terminal connected respectively with a firstterminal of the second transistor and one end of the storage capacitor.

The second transistor includes the gate at which a fifth control signalis received, and a second terminal connected with the drain of the drivetransistor.

The storage capacitor includes the other end connected with the gate ofthe drive transistor.

The third transistor includes a first terminal connected with the gateof the drive transistor, the gate at which a sixth control signal isreceived, and a second terminal connected with a first terminal of thefourth transistor.

The fourth transistor includes the gate at which the sixth controlsignal is received, and a second terminal connected with the source ofthe drive transistor.

The drive transistor includes the drain at which a first power supplysignal is received.

The fifth transistor includes a first terminal connected with the sourceof the drive transistor, the gate at which the fifth control signal isreceived, and a second terminal connected respectively with a firstterminal of the sixth transistor, the gate of the sixth transistor andthe gate of the seventh transistor.

The sixth transistor includes a second terminal at which a second powersupply signal is received.

The seventh transistor includes a first terminal connected with thecathode of the organic light emitting diode, and a second terminal atwhich the second power supply signal is received.

At this time, the first transistor is T2 in FIG. 10, the secondtransistor is T3 in FIG. 10, the storage capacitor is Cs in FIG. 10, thethird transistor is T4 in FIG. 10, the fourth transistor is T5 in FIG.10, the drive transistor is Td in FIG. 10, the fifth transistor is T7 inFIG. 10, the sixth transistor is T8 in FIG. 10, the seventh transistoris T9 in FIG. 10, and the organic light emitting diode is the OLED inFIG. 10.

Optionally, the pixel circuit according to the embodiment of the presentinvention further includes an eighth transistor and a first capacitor,where the eighth transistor includes a first terminal connected with asecond terminal of the third transistor, the gate at which a fifthcontrol signal is received, and a second terminal connected with thegate of the drive transistor; and the first capacitor includes one endconnected with a second terminal of the third transistor, and the otherend at which the second power supply signal is received.

At this time the eighth transistor is T6 in FIG. 11, and the firstcapacitor is C1 in FIG. 11.

Optionally, the pixel circuit according to the embodiment of the presentinvention further includes a ninth transistor, wherein a first terminalof the seventh transistor is connected with the cathode of the organiclight emitting diode through the ninth transistor, and the gate of theninth transistor is connected with a second terminal of the fifthtransistor.

At this time, the fifth transistor is T10 in FIG. 12 or FIG. 13, thesixth transistor is T11 in FIG. 12 or FIG. 13, the seventh transistor isT12 in FIG. 12 or FIG. 13, and the ninth transistor is T13 in FIG. 12 orFIG. 13.

The first terminal of the transistor as referred to in the embodiment ofthe present invention may be the source (or the drain) of thetransistor, and the second terminal of the transistor may be the drain(or the source) of the transistor. If the source of the transistor isthe first pole, then the drain of the transistor is the second pole; andif the drain of the transistor is the first pole, then the source of thetransistor is the second pole. The connection s referred to in theembodiment of the present invention includes a physical connection andan electrical connection.

An embodiment of the present invention provides a display panel, asillustrated in FIG. 16, including a pixel circuit 61 according to anyone of the embodiments above of the present invention and an arraysubstrate 162.

When the display panel includes the plurality of pixel circuits, thefirst control signal, the second control signal and the third controlsignal received by each of the pixel circuits may come from differentsignal sources or may be derived from a signal outputted by the samesignal source.

Similarly, when the display panel includes the plurality of pixelcircuits, the fourth control signal, the fifth control signal and thesixth control signal received by each of the pixel circuits may comefrom different signal sources or may be derived from a signal outputtedby the same signal source.

An embodiment of the present invention provides a display device, asillustrated in FIG. 17, including the display panel 171 according to theembodiment of the present invention and a housing 172 of the displaydevice.

Those skilled in the art may appreciate that the drawings are merelysimplified block and circuit diagrams of preferred embodiments of thepresent invention and not all of the components or flows in the drawingsare necessarily necessary for the present invention to be put intopractice.

Those skilled in the art may appreciate that the components in thedevices according to the embodiments may be distributed in the devicesof the embodiments as described in the embodiments or located in one ormore other devices than the embodiments in question while being adaptedcorrespondingly. The components in the foregoing embodiments may beintegrated into a component or subdivided into a plurality ofsub-components.

The foregoing embodiments of the present invention have been numberedmerely for the convenience of their description but will not indicateany precedence of one embodiment over the other.

Evidently those skilled in the art may make various modifications andvariations to the present invention without departing from the spiritand scope of the present invention. Thus the present invention is alsointended to encompass these modifications and variations thereto so longas the modifications and variations come into the scope of the claimsappended to the present invention and their equivalents.

What is claimed is:
 1. A pixel circuit for driving an organic lightemitting diode, the pixel circuit comprising a signal loading component,a storage capacitor, a compensation component, a mirror component, and adrive transistor, wherein the signal loading component comprises a firstend configured to receive an image data signal, a second end configuredto receive a first control signal, and a third end configured to connectwith a gate of the drive transistor; the storage capacitor comprises afirst end connected with a drain of the drive transistor and a secondend connected with the gate of the drive transistor; the drivetransistor is configured to generate current at the drain thereofaccording to a difference between a signal at the gate thereof and asignal at a source thereof in a light emission stage, wherein the drainof the drive transistor is configured to receive a first power supplysignal; the compensation component comprises a first end configured toreceive a second control signal, a second end connected with the gate ofthe drive transistor, and a third end connected with the source of thedrive transistor; the mirror component comprises a first end configuredto receive a third control signal, a second end connected with thesource of the drive transistor, a third end configured to receive asecond power supply signal, and a fourth end connected with a cathode ofthe organic light emitting diode; and the organic light emitting diodecomprises an anode configured to receive the first power supply signal.2. The pixel circuit according to claim 1, wherein the signal loadingcomponent is configured to transmit the image data signal to the gate ofthe drive transistor in a data transmission stage; the storage capacitoris configured to store the signal at the gate of the drive transistor;the compensation component is configured to connect the gate of thedrive transistor to the source of the drive transistor in a thresholdvoltage compensation stage to generate a drive signal from the imagedata signal stored in the storage capacitor in the data transmissionstage; and the mirror component is configured to mirror the currentgenerated by the drive transistor at the drain thereof into the organiclight emitting diode in the light emission stage, such that the organiclight emitting diode emits light with a difference in voltage betweenthe first power supply signal and the second power supply signal.
 3. Thepixel circuit according to claim 1, wherein the first end of the signalloading component is connected to the third end of the signal loadingcomponent in the data transmission stage; the second end of thecompensation component is connected to the third end of the compensationcomponent in the threshold voltage compensation stage to generate thedrive signal from the image data signal stored in the storage capacitor;and the second end of the mirror component is connected to the third endof the mirror component in the light emission stage.
 4. The pixelcircuit according to claim 1, wherein the signal loading componentcomprises a first transistor: a first terminal of the first transistoris the first end of the signal loading component, the gate of the firsttransistor is the second end of the signal loading component, and asecond terminal of the first transistor is the third end of the signalloading component; and the first transistor is turned on in the datatransmission stage and turned off in the threshold voltage compensationstage and the light emission stage.
 5. The pixel circuit according toclaim 1, wherein the compensation component comprises a fourthtransistor and a fifth transistor: wherein a gate of the fourthtransistor is the first end of the compensation component, a firstterminal of the fourth transistor is the second end of the compensationcomponent, and a second terminal of the fourth transistor is connectedwith a first terminal of the fifth transistor; the gate of the fifthtransistor is the first end of the compensation component, and a secondterminal of the fifth transistor is the third end of the compensationcomponent; and both the fourth transistor and the fifth transistor isconfigured to be turned on in the threshold voltage compensation stageand to be turned off in the data transmission stage and the lightemission stage.
 6. The pixel circuit according to claim 5, wherein thecompensation component further comprises a sixth transistor and a firstcapacitor: wherein both a first terminal of the sixth transistor and afirst end of the first capacitor is connected with the second terminalof the fourth transistor; the second power supply signal is received ata second end of the first capacitor; a signal received at the gate ofthe sixth transistor is the same as the signal received at the first endof the mirror component, and a second terminal of the sixth transistoris connected with the gate of the drive transistor; the sixth transistoris turned on in the light emission stage and turned off in both the datatransmission stage and the threshold voltage compensation stage; and thefirst capacitor is charged in the threshold voltage compensation stage,such that the drive transistor generates the drive signal from thestored image data signal.
 7. The pixel circuit according to claim 1,wherein the mirror component comprises a seventh transistor, an eighthtransistor and a ninth transistor: wherein a first terminal of theseventh transistor is the second end of the mirror component, the gateof the seventh transistor is the first end of the mirror component, anda second terminal of the seventh transistor is connected respectivelywith a first terminal of the eighth transistor, the gate of the eighthtransistor and the gate of the ninth transistor; a second terminal ofthe eighth transistor is the third end of the mirror component; and afirst terminal of the ninth transistor is the fourth end of the mirrorcomponent, and a second terminal of the ninth transistor is the thirdend of the mirror component.
 8. The pixel circuit according to claim 1,wherein the mirror component is further configured to perform negativefeedback control on the current flowing through the organic lightemitting diode so as to stabilize the current flowing through theorganic light emitting diode.
 9. The pixel circuit according to claim 8,wherein the minor component comprises a tenth transistor, an eleventhtransistor, a twelfth transistor and a thirteenth transistor: wherein afirst terminal of the tenth transistor is the second end of the mirrorcomponent, the gate of the tenth transistor is the first end of themirror component, and a second terminal of the tenth transistor isconnected respectively with a first terminal of the eleventh transistor,the gate of the eleventh transistor, the gate of the twelfth transistorand the gate of the thirteenth transistor; a second terminal of theeleventh transistor is the third end of the mirror component; and afirst terminal of the twelfth transistor is connected with a firstterminal of the thirteenth transistor, second terminal of the twelfthtransistor is the third end of the mirror component, and a secondterminal of the thirteenth transistor is the fourth end of the mirrorcomponent.
 10. A display panel comprising a plurality of pixel elements,each of the pixel elements comprising an organic light emitting diodeand a pixel circuit according to claim 1 for driving the organic lightemitting diode.
 11. A pixel circuit for driving an organic lightemitting diode, the pixel circuit comprising a signal loading component,a storage capacitor, a compensation component, a mirror component, and adrive transistor, wherein the signal loading component comprises afourth end configured to receive an image data signal, a fifth endconfigured to receive a fourth control signal, a sixth end connectedwith a first end of the storage capacitor, a seventh end configured toreceive a fifth control signal, an eighth end connected with a drain ofthe drive transistor; the compensation component comprises a first endconfigured to receive a sixth control signal, a second end connectedwith a gate of the drive transistor, and a third end connected with asource of the drive transistor; the mirror component comprises a firstend configured to receive the fifth control signal, a second endconnected with the source of the drive transistor, a third endconfigured to receive a second power supply signal, and a fourth endconnected with a cathode of the organic light emitting diode; thestorage capacitor comprises the first end connected with the sixth endof the signal loading component, and a second end connected with thegate of the drive transistor; the drive transistor is configured togenerate a current at the drain thereof according to a differencebetween a signal at the gate thereof and a signal at the source thereofin a light emission stage, wherein the drain of the drive transistor isconfigured to receive a first power supply signal; and the organic lightemitting diode comprises an anode configured to receive the first powersupply signal, and the cathode connected with the fourth end of themirror component.
 12. The pixel circuit according to claim 11, whereinthe signal loading component is configured to transmit the image datasignal to the gate of the drive transistor in a data transmission stage;the compensation component is configured to connect the gate of thedrive transistor to the source of the drive transistor in a thresholdvoltage compensation stage to generate a drive signal from the imagedata signal stored in the storage capacitor in the data transmissionstage; the mirror component is configured to mirror the currentgenerated by the drive transistor at the drain thereof into the organiclight emitting diode in the light emission stage, such that the organiclight emitting diode emits light with a difference in voltage betweenthe first power supply signal and the second power supply signal; andthe storage capacitor is configured to store the signal at the gate ofthe drive transistor.
 13. The pixel circuit according to claim 11,wherein the fourth end of the signal loading component is connected tothe sixth end of the signal loading component in the data transmissionstage, and disconnected from the sixth end of the signal loadingcomponent in the threshold voltage compensation stage and in the lightemission stage, the sixth end of the signal loading component isdisconnected from the eighth end of the signal loading component in thedata transmission stage and in the threshold voltage compensation stageand connected to the eighth end of the signal loading component in thelight emission stage; the second end of the compensation component isconnected to the third end of the compensation component in thethreshold voltage compensation stage so as to generate the drive signalfrom the image data signal stored in the storage capacitor; and thesecond end of the mirror component is connected to the third end of themirror component in the light emission stage.
 14. The pixel circuitaccording to claim 11, wherein the signal loading component comprises asecond transistor and a third transistor: wherein a first terminal ofthe second transistor is the fourth end of the signal loading component,the gate of the second transistor is the fifth end of the signal loadingcomponent, and the second terminal of the second transistor is the sixthend of the signal loading component; and a first terminal of the thirdtransistor is the sixth end of the signal loading component, the gate ofthe third transistor is the seventh end of the signal loading component,and a second terminal of the third transistor is the eighth end of thesignal loading component; the second transistor is turned on in the datatransmission stage and turned off in the threshold voltage compensationstage and the light emission stage; and the third transistor is turnedon in the light emission stage and turned off in the data transmissionstage and the threshold voltage compensation stage.
 15. The pixelcircuit according to claim 11, wherein the compensation componentcomprises a fourth transistor and a fifth transistor: wherein a gate ofthe fourth transistor is the first end of the compensation component, afirst terminal of the fourth transistor is the second end of thecompensation component, and a second terminal of the fourth transistoris connected with a first terminal of the fifth transistor; and the gateof the fifth transistor is the first end of the compensation component,and a second terminal of the fifth transistor is the third end of thecompensation component; and both the fourth transistor and the fifthtransistor are configured to be turned on in the threshold voltagecompensation stage and to be turned off in the data transmission stageand the light emission stage.
 16. The pixel circuit according to claim15, wherein the compensation component further comprises a sixthtransistor and a first capacitor: wherein both a first terminal of thesixth transistor and a first end of the first capacitor is connectedwith the second terminal of the fourth transistor; the second powersupply signal is received at a second end of the first capacitor; asignal received at the gate of the sixth transistor is the same as thesignal received at the first end of the mirror component, and a secondterminal of the sixth transistor is connected with the gate of the drivetransistor; the sixth transistor is turned on in the light emissionstage and turned off in both the data transmission stage and thethreshold voltage compensation stage; and the first capacitor is chargedin the threshold voltage compensation stage, such that the drivetransistor generates the drive signal from the stored image data signal.17. The pixel circuit according to claim 11, wherein the mirrorcomponent comprises a seventh transistor, an eighth transistor and aninth transistor: wherein a first terminal of the seventh transistor isthe second end of the mirror component, the gate of the seventhtransistor is the first end of the mirror component, and a secondterminal of the seventh transistor is connected respectively with afirst terminal of the eighth transistor, the gate of the eighthtransistor and the gate of the ninth transistor; a second terminal ofthe eighth transistor is the third end of the mirror component; and afirst terminal of the ninth transistor is the fourth end of the mirrorcomponent, and a second terminal of the ninth transistor is the thirdend of the mirror component.
 18. The pixel circuit according to claim11, wherein the mirror component is further configured to performnegative feedback control on the current flowing through the organiclight emitting diode so as to stabilize the current flowing through theorganic light emitting diode.
 19. The pixel circuit according to claim18, wherein the minor component comprises a tenth transistor, aneleventh transistor, a twelfth transistor and a thirteenth transistor:wherein a first terminal of the tenth transistor is the second end ofthe mirror component, the gate of the tenth transistor is the first endof the mirror component, and a second terminal of the tenth transistoris connected respectively with a first terminal of the eleventhtransistor, the gate of the eleventh transistor, the gate of the twelfthtransistor and the gate of the thirteenth transistor; a second terminalof the eleventh transistor is the third end of the mirror component; anda first terminal of the twelfth transistor is connected with a firstterminal of the thirteenth transistor, second terminal of the twelfthtransistor is the third end of the mirror component, and a secondterminal of the thirteenth transistor is the fourth end of the mirrorcomponent.
 20. A display panel comprising a plurality of pixel elements,each of the pixel elements comprising an organic light emitting diodeand a pixel circuit according to claim 11 for driving the organic lightemitting diode.